The present invention relates to building tires and, more particularly, to methods and apparatus for loading beads on green tire carcasses, particularly in the context of an automatic tire building system having a sequence of work stations, and also in cases that the carcass has bumps resulting from insert components and the like.
It is known that in making vehicle tires, for example for automobiles, that manufacture of a so-called carcass is first achieved by successively assembling several different components. In other words, the different carcass types included in a production range can be distinguished from one another depending on the presence thereon of the various accessory components and/or the typology of the accessory components themselves.
By way of example, when carcasses for tubeless tires are to be produced, that is tires that in use do not require the presence of an inner tube, the main components can be considered to include a so-called inner liner that is a layer of elastomeric air-impervious material, a carcass ply, a pair of annular metal elements, commonly referred to as bead cores (or simply xe2x80x9cbeadsxe2x80x9d), around which the opposite ends of the carcass ply are folded, as well as a pair of sidewalls made of elastomeric material, extending over the carcass ply at laterally opposite positions. The accessory components may in turn comprise of one or more additional carcass plies, one or more reinforcing bands for overlying the carcass ply or plies at the areas turned up around the bead cores (chafer strips), and others.
As disclosed in U.S. Pat. No. 5,554,242, two stage tire building with a first stage tire building drum in combination with a second stage tire building drum is well known and established in the art with the building drums being both in line and offset from each other. It is further known to have two-stage tire building with a single drum swinging between the first stage position and second stage position where a band builder is in line with the first stage building drum. For this system, individual breaker application and single piece tread rubber are applied at the second stage while components such as apex chafers and shoulder wedges are applied at the first stage. The above components are made in separate operations and stored for use as needed in the two-stage building process.
U.S. Pat. No. 5,354,404 discloses a system for assembling green tires with a two stage process where the assembly is automatic and requires a small amount of floor space.
It has been known in the prior art, as disclosed in U.S. Pat. No. 2,319,643, to manufacture tires on a line with a plurality of building drums that are chucked up at each station.
Also, as disclosed in U.S. Pat. No. 1,818,955, tires can be manufactured on a line with a plurality of building drums xe2x80x9carranged in a train or series and connecting means is provided for translating the cores from one device to the next.xe2x80x9d The connectivity between the tire cores leads to the inability to change the machine to accommodate various sized tire constructions.
In modern production processes, the assembling of the different components is carried out in automated plants including a plurality of assembling drums moved following a precise working sequence in accordance with the manufacturing process to be executed. For example, as disclosed in U.S. Pat. No. 5,411,626, these plants can consist of a plurality of work stations disposed consecutively in side by side relation, each of which lends itself to carry out the application of a predetermined component onto the assembling drums that in turn are brought in front of it.
EPO 0,105,048 discloses a tire assembly means employing a conveyor to transport a plurality of tire building drums to a plurality of applicator stations wherein various components are applied to the tire building drums at the various applicator stations in order to fabricate a tire when the tire building drums have made a complete transversal of the conveyor, wherein the tire building drums are maintained in an angled relationship with respect to the conveyor and the applicator stations.
In particular there are primary work stations intended for application of the main components, which are always active, irrespective of the carcass type being produced. Alternated with the various primary work stations there are one or more auxiliary, work stations, intended for application of accessory components, if required. The activation or deactivation state of these auxiliary stations depends on the carcass type in progress of manufacture.
Typical tire building machines comprise a tire build drum around which the tire components are wrapped in successive layers including, for example, an innerliner, one or more carcass plies, optional sidewall stiffeners and bead area inserts (e.g., apex), sidewalls and bead wire rings (beads). After this layering, the carcass ply ends are wrapped around the beads, the tires are blown up into a toroidal shape, and the tread/belt package is applied. Typically the tire build drum is in a fixed location on the plant floor, and the various layers of components are applied manually or automatically using tooling registered to reference points on the fixed drum in order to ensure component placement with the desired degree of precision. The tooling is generally fixed relative to the tire build drum, for example a guide wheel on an arm extending from the same frame (machine base) which supports the tire build drum.
According to the invention, a method is provided for mounting two beads on a tire carcass which is being laid up on tire building drum, wherein the drum has a free end and an opposite end which is supported by a drum support (or comparable impediment to installing a bead from the opposite end of the drum), and the drum has a first area on its surface where the tire carcass will be laid up. The method comprises disposing a first of the two beads on the drum in an area which is between the carcass layup area and the drum support. The bead is moved into this position from the free end of the drum, and this is done before the process of laying up the carcass has resulted in ihere being bumps in the outer surface of the tire carcass. This may be prior to any carcass components have been laid up, or after an inner liner has been laid up, or after an inner liner and inserts and a ply have been laid up on a drum having pockets (recesses) to alleviate bump formation. With the bead xe2x80x9cparkedxe2x80x9d on the drum, yet out of the way of laying up the carcass, the carcass may be laid up. After laying up the carcass the bead is moved into position on the carcass. Then, additional tire components may be laid up on the tire carcass and/additional steps performed in the formation of the carcass. The other bead is installed onto the carcass in a conventional manner. In this manner, both beads may be installed from a one free end of a drum.
The present invention is particularly useful in conjunction with a system for simultaneously building a plurality of tire carcasses, such as is disclosed in the aforementioned U.S. patent Application Ser. No. 09/957,785 entitled METHOD FOR MANUFACTURING TIRES ON A FLEXIBLE MANUFACURING SYSTEM, and described hereinbelow with respect to FIGS. 1A, 1B, 1C, 1D and 2. The method disclosed therein generally comprises the tire building steps of establishing a sequence of at least three and up to ten work stations; advancing at least three disconnected tire building drums along a working axis extending through the at least three work stations; and applying one or more tire components to the tire building drums at each of the work stations. Then the resulting green tire carcass is removed at the last of the work stations. Finally, the tire building drum is advanced from the last work station after the green carcass has been removed to the first work station.
Other objects, features and advantages of the invention will become apparent in light of the following description thereof.
Reference will be made in detail to preferred embodiments of the invention, examples of which are illustrated in the accompanying drawing figures. The figures are intended to be illustrative, not limiting. Although the invention is generally described in the context of these preferred embodiments, it should be understood that it is not intended to limit the spirit and scope of the invention to these particular embodiments.
Certain elements in selected ones of the drawings may be illustrated not-to-scale, for illustrative clarity. The cross-sectional views, if any, presented herein may be in the form of xe2x80x9cslicesxe2x80x9d, or xe2x80x9cnear-sightedxe2x80x9d cross-sectional views, omitting certain background lines which would otherwise be visible in a true cross-sectional view, for illustrative clarity.
Elements of the figures are typically numbered as follows The most significant digit (hundreds) of the reference number corresponds to the figure number. Elements of FIG. 1 are typically numbered in the range of 100-199. Elements of FIG. 2 are typically numbered in the range of 200-299. Similar elements throughout the drawings may be referred to by similar reference numerals. For example, the element 199 in a figure may be similar, and possibly identical to the element 299 in another figure. Elements of the figures can be numbered such that similar (including identical) elements may be referred to with similar numbers in a single drawing. For example, each of a plurality of elements collectively referred to as 199 may be referred to individually as 199a, 199b, 199c, etc. Or, related but modified elements may have the same number but are distinguished by primes. For example, 109, 109xe2x80x2, and 109xe2x80x3 are three different elements which are similar or related in some way, but have significant modifications, e.g., a tire 109 having a static imbalance versus a different tire 109xe2x80x2 of the same design, but having a couple imbalance. Such relationships, if any, between similar elements in the same or different figures will become apparent throughout the specification, including, if applicable, in the claims and abstract. Sometimes, similar elements are referred to with the suffixes -L and -R (e.g., 133L, 133R), which generally indicate left and right, as may be viewed in the drawing. Such elements may be referred to collectively simply by their number (e.g., 133) with no L/R suffix.